Fuel injection system

摘要

A booster unit is provided in an injector of a fuel injection system. The booster unit includes a booster piston accommodated in a pressure chamber, and a discharge valve capable of discharging fuel in a backpressure chamber. A controller includes an indication-value setting step which sets an indication value of a target pressure in a common rail in correspondence to an engine operation state, a determination step which determines whether or not the indication value of the pressure in the common rail is in a direction of reduction to be lower in comparison to a previously set indication value, and a booster piston pseudo-operation step which opens the discharge valve at timing other than injection operation of the injector when the determination step has determined that the indication value is in the direction of reduction.